CVE-2026-39245 Path traversal in n/a
An attacker can exploit flawed path validation to write arbitrary files outside the intended directory, potentially leading to code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-39245?
CVE-2026-39245 is a medium-severity path traversal vulnerability in n/a, published on 9 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
decompress before 4.2.2 contains an improper path containment check that enables directory traversal and arbitrary file write. The safeMakeDir function (index.js line 29) and the extraction path validation (index.js line 106) use String.indexOf() to verify the resolved path is within the output directory: realDestinationDir.indexOf(realOutputPath) !== 0. This check is flawed because it does not enforce a path separator boundary. For example, "/tmp/app_config".indexOf("/tmp/app") returns 0, incorrectly passing the check even though /tmp/app_config is outside /tmp/app. Combined with the unvalidated symlink creation in the same package, an attacker can write arbitrary files to directories adjacent to the extraction target. This is a bypass of the fix for CVE-2020-12265. The correct check requires appending a path separator: realParentPath.indexOf(realOutputPath + path.sep) !== 0.
Weakness: CWE-22
Which versions are affected by CVE-2026-39245?
It affects 1 product.
Products include Decompress Project Decompress.
How do I fix CVE-2026-39245?
Upgrade to a fixed version.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-39245 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-39245 exists.
Other vulnerabilities in n/a
Sources
Also known as GHSA-qcj4-cj8p-fhf4.